248 



FORESTRY AND IRRIGATION 



May 



bank has been built to the proper 

 height it is smoothed and sodded. On 

 the right-hand side of the figure is the 

 pipe or wooden flume from the wind- 

 mill and on the left-hand side is shown 

 the outlet box, which is usually built 

 of 2-inch plank. This is closed by some 

 simple form of wooden gate or valve, 

 either lifted by means of a screw or 

 hinged so as to open outward, and is 



held in place by the pressure of the 



water against it. 



The square reservoir is the form 

 usually adopted. The mills, as in the 

 other cases, are placed on each side, 

 pumping through short wooden flumes 

 over the bank. These reservoirs are 

 not only used for holding water for 

 irrigation, but with a little care serve 

 as ponds for raising fish. 



COST OF RECLAMATION WORK 



How Cos! of Western Irrigation Work 

 Compares with Like Work Elsewhere 



f^\NE of the most surprising features 

 ^^^ connected with the work of the Re- 

 clamation Service, as well as the one 

 affording highest gratification, is the 

 cost of structures compared with those 

 which have become familiar to engi- 

 neers in the East. 



When the reclamation work was in- 

 augurated it was a matter of conject- 

 ure whether or not the standards of 

 cost for dams, canals, etc., that had 

 been established by engineering prac- 

 tice in the eastern part of the country, 

 could be relied upon as a basis of 

 estimates of the cost of the proposed 

 western structures. As the work has 

 progressed it has become more and 

 more evident that many classes of en- 

 gineering work in the west can be per- 

 formed considerably cheaper than in 

 the East, and at the same time the 

 natural conditions are such that these 

 structures are economical and effec- 

 tive. 



If we take, for example, the three 

 great masonry dams now being erect- 

 ed for the purpose of storing water, 

 viz. : the Roosevelt dam in Arizona, 

 the Pathfinder dam in southeastern 

 Wyoming, and the Shoshone dam in 

 northwestern Wyoming, we shall find 

 that the effective storage capacity and 

 costs are far below those of some of 

 the great eastern dams like the New 

 Croton in New York, and the Wachu- 

 etl in Massachusetts. The heights of 



these dams are as follows : Roosevelt, 

 280 feet; Pathfinder, 210 feet; Sho- 

 shone, 308 feet ; New Croton, 297 feet, 

 and Wachusett, 207 feet. These 

 heights are measured from the foun- 

 dation stones to parapet in each case, 

 and they show that the Shoshone is the 

 highest, while the New Croton is sec- 

 ond and the Roosevelt third. If, how- 

 ever, the height above the river bed 

 be considered, that is, the effective 

 storage height, the New Croton is the 

 lowest. The order is then as follows : 

 Shoshone, 240 feet ; Roosevelt, 230 

 feet ; Pathfinder, 200 feet ; Wachusett, 

 185 feet ,and the New Croton, 157 

 feet. In other words, about 50 per 

 cent of the masonry in the New Croton 

 dam is below ground and is service- 

 able for foundation purpose only. 



It is interesting to note the compar- 

 ative reservoir capacities. While the 

 New Croton dam is the largest in the 

 world from the standpoint of its 

 amount of masonry, the storage capa- 

 city of the reservoir formed by it is 

 by far the lowest of any of those above 

 mentioned. In fact, from a stand- 

 point of storage economy, the New 

 Croton reservoir is one of the poorest 

 that has been constructed in recent 

 years. The dam contains 833,000 

 cubic yards of masonry and was erect- 

 ed at a cost of $7,600,000. The capa- 

 city of the reservoir formed by it is 

 4,000,000,000 cubic feet, or a cost of 



